Entities Forgetting They're Entities?

So I was mapping, trying to make a spawnroom. And basically, I'd tie one thing to an entity, make all the settings and hit "Apply", go do something else, and come back to the previous thing and suddenly it's a solid with 6 faces and no func status. I can tie an entity to it, and its original name and entity type are shown on the 2D views, but apparently they're reverting back to solids. I know that I'm hitting Apply, because everytime I tie it back to an entity, the name gets changed, and that's one of the items I input.

Taking multiple brushes and making them one single brush entity is basically a form of grouping. Thus it allows you to move individual brushes by temporarily forgetting they're "grouped" via entity relationship.